Band brake acting in both directions of rotation



April 7, 1925. 1,532,919

M. MULLER BAND BRAKE ACTING IN BOTH DIRECTIONS 0F ROTATION Filed April 4 1922 2 Sheets-Sheet 1 April 7, 1925. 1,532,919

, M. MULLER BAND BRAKE ACTING IN BOTH DIRECTIONS 0F ROTATION Filed April 1, 1922 2 sheets-sheet 2 Even/or.-

ilimzYziin 67" Affair/1e Patented Apr. '7, 1925.

UNITED STATES MAXIMILIAN MU'LLER, F TEMPELHOF, NEAR BERLIN, GERMANY.

BAND BRAKE ACTING IN BOTH DIRECTIONS 0F ROTATION.

' Application filed April 4, 922. Serial N5. 549,585.

To all whom it may concern:

Be it known that I, MAXIMILIAN Mi'JLLER, a subject of Czechoslovakia, residing at Tempelhof, near Berlin, Germany, have 1nvented certain new and useful Improvements in Band Brakes Acting in Both Directions of Rotation, of which the following is a specification.

The present invention relates to a bandbrake, which will act in both directions of rotation and it is characterized in that the pulling force at the engaging end of the strap or band is created by means of the friction on the brake drum. In order to carry this idea into practice various ways are diagrammatically illustrated in the drawings, in which, thesa'me reference characters designate like parts throughout Figs. 1, 2, 3 and 4 are side views of various forms of the invention ofwhich Fig. 4 shows the preferred form,

Fig. 5 is a fragmentary side View of another form of the invention,

Figs. 5 6, 7 and 8 are side views of still other forms of the invention, I

Fig. 9 is a side view of a solenoid, and

Fig. 10 shows a wiring diagram for an electroma netic brake.

In the first place the band proper may be utilized as a friction-source for the pulling force in said band. For instance in Fig. 1 the shaft to be braked is designated by A and on said shaft is keyed a braking drum 1. Around this drum the strap 2 2 is led, the ends of which lead to the fixed point 4. If a roller 43 is pressed upon said band, the latter is conducted by the rotation of the drum between the drum and said roller in the direction of rotation and under the pressure of the roller 43 a friction is caused between the band and drum, which creates a pulling force in, the said band, so that a braking action is exerted. If the drum is rotating in the direction of the arrow as indicatedin the drawing, the end 2 of the band is tightened and exerts a braking action, while the end 2 of the band becomes slack.

Another mode of execution is illustrated in Fig. 2, in which the embraced sector "becomes essentially larger. A again represents the shaft, 1 the drum of the brake, 2 and 2 the band. The latter is provided with stops riveted upon it, consisting for in-. stance of flat iron members'5 and 5, comprising stops, which are capable of abutting against fixed stops 6 or 6. It is supposed that the band is entirely flexible or at least is provided with a flexible part betweenthe points 5 and 5. If the roller 43is pressed down again, the aforesaid procedure will be repeated, and if the direction of rotation of the drum 1 is counter clockwise as shown by the arrow, the stop 5 on the band will abut against the fixed stop 6 and a powerful 6 braking action will be obtained while the portion of the band between the ."roller43 and the stop 5' on the band becomes slack and is forced up. This stage is illustrated in Fig.2. p r.

If the band proper'is utilized as a source of friction, the characteristic feature of the invention is, that one roller is pressed against the band in such a way that an arc of the drum engages with the corresponding are of the'band according to the direction,

. of rotation either to the left hand or to the right hand of the point where the roller is applied.

Instead of employing the band proper as V the band 2 and 2 with its stops 5 and. 5;

6 and 6 are fixed stops as illustrated in Fig. 2. The magnet 20 upon which an exciting coil 8 is wound, is connected with both ends of the band'by means of thechains 21 and 22. If the magnet is excited it will adhere to the brake drum, and be taken along by the latter and will thus create a pulling force on the chains according to the direction of rotation, so that the band will engage and cause a, braking action. The preferred form of the. invention is illustrated in Fig.4 in which all parts are similarly designated as in Fig. 3'but in'lieu of a magnet a roller 3 is provided. If the latter is pressed by any suitable mechanical means againstthe drum 1 it will be turned by the friction and according to thedirection of rotation either'the chain 21 or 22 will be tightened thus producing a braking action. 105 This mode of execution is superior to all those already described'since it is very easy 60 H i V These newbrakes mayv particularly be emon thel band. It is only necessary to conr efiff a the route as a $tei 'Ped roller in such a manner, that the frictional force of the brake drumacts upon the larger radius of'the roller, while the chain leading to the end of the band engages a smaller radius of the'said stepped roller. Another mode of execution is illustratedin Fig. 5, in whichthddifi'erence consists merely in ithat the roller does not press the amm diaa y; but? that a. special nf f t 't'ion' of rotatioin cau'sing the braking action. A similar arrangementis shown in Fig 512, Here 'the' roller is substituted I by a ifto othetlfjvheel 3, which is in engagement fwitlifthefrictionmember 23 and the chains";

secured to thefr'ame 12 being eithen'screwed 'j member? is :arraagea between roller 43' and", um l fr'om which member the chains 21 and22 leadto the ends ofthe band. It is j obviousithat assoon as'a mechanical presf ii' s ure "i s-"exerted uponsaid roller, the friction InemberQ is carried along by thebraking drumfwhile'tlie latter is rotating, sothat a 2 1 22 is! tightened according to the direc- "en a e the toothed' wheelf The advantage gained is so to speak considerably greater. than thematic ofthe two radii. The reason P for thisis that the force which is created in 1mi at b r s lv s me fnents; the directlon of one of which 18 ident'ical with the direction of the roller-lever,

nent is that of the radius of the'brake drum. This latter component has to be added to the external pressure by fwhereas thedirectio'n of the second compowhich the roller is 'pressedagainst the drum.

'K'lsinall mathematical deduction shows itha t'if z i's'th'e force of the chain, P'tlle j teriorpressure with which the roller is g pressedagainst the drum, 1* the'small radius ,of the roller, 7* the large radius o'fthc roller R the radius of the brake drum and u the. coeflicient offriction between the effected in a "known-manner either by hand,

roller and drum;"then follows 1:-

played with vehicles, sincet-hey consume only an extraordinarily small amount of powerv For actuatmg, -suchv brakesrequire hardly "one hundredth part of the work i requir'ed 'piilling for'ce is created and either the chain by the block-brakes used almost exclusively up to the present. This advantage is derived fromthe fact that with these new brakes the force of; the vehicle or -car will, while braking; accomplish a great portion of'that work, which had to be done by hand in the block-ibrakeshitherto used.

'erat'ion, which cause 1a violent and -iindesirable shaking- This will at once disappear, I

if the whole braking device is'Y'arr'anged upon the axle of the car asillustrated in Fig- 6, in which Adesignates the axle of braking drum a sliding b'earinglis provided,

"which rests in-aicastfseeel frame .12; which carries the solenoid 24,- and the lOll IffleViGl' 7 with its pivot point 25, inwhich the roller 3 is pivoted. .The fixedst ops .6, 6 are rigidly bearing of the frame uponthe shaft ofgthe braking-drum it may of course just as well bear. directly on said' axle; It is alsofpossible to make use of the-axle boxes -.of the .car for thatpurpose, ,or of the axle bearings of electric motors if such areprovided. The important point alwaysremains, that af'special frame is bearingon'the axle either directly or indirectly in such a manner that it only executesqa rotating movement in relation tosai'd axle.

Operating these "new, band brakes can be mechanically orby; air or electrically by magnets: Various important improvements On the one hand thepressingforcecan be eifected b'y"means of a magnet; as shown in Fig. 8. Butthe operation canalso be effected electrically by interposition of the vroller as shown in Fig. 7: A solenoid is-pro vided here which-will pull its piston if'it is excited by acurrent'and thus turn tlie'roller lever '7 "pivoted at point 25. in such a way that the roller 3 causes a pressure. The re the car; upon which is tightlyiikeyed the brake drum 1,,No w" on the, shaft, ofithe Inc mainingparts of-this illustration correspond :with the constructionshown in Fig. 4 and will be understood without any further ex- 'planation. 26 'is'aspring designed to with draw therollerafter'the fbraking operation the braking action no current is active.

and to pull outithe plunger of the solenoid .is active during the braking operation and the control of the braking power can be simply efiected in that the intensity of the magnet or solenoid is increased or decreased.

It is however possible to effect quite a new electrical operation, in which during the pressing force of the roller is effected by means of the expansion of springs, which after the braking action is finished, are again put under tension by means of an electromagnet, it is hereby accomplished, that during the'braking operation disturbances in the conductor, as for instance, defective controller or coupling contacts between the cars or breakage in car-wiring are without the least influence on safety of the brake. Of course part of the train which has become detached for some cause,'will be braked automatically. For compressing the spring preferably solenoids are employed as electromagnets.

The electric energy required for com pressing the spring by means of the 'solenoid can be supplied by a current from over-head conductors, since with these brakes the absence of current in the overhead conductor will not prevent the braking action, but on the contrary it will permit such action. -Constructional forms oi this kind of actuation are illustrated in Figs. '8 and 6. 7 isthe roller lever pivoted at 25 and 24 the solenoid. The lever 7 is pivoted to the stationary member 12 which has a stop 6 at one end thereof which cooperates with the stop 5 on the brake band. The core of the latter extends far beyond it and carries at this free end a spring-plate and between thisspring-plate and the casing of the solenoid is disposed thebraking spring 10. If the solenoid is energized the latter will generate such a power, that the spring 10 is compressed by the aid of the spring-plate. In this state, represented in Figs. .6 and 8 the spring is compressed, the roller is not in engagement with the drum and no braking action is effected. This position of the brake .is maintained when driving but if the current in the solenoid is interrupted the spring advances the plunger of the solenoid, and the spring-plate abuts against the roller lever 7 turning the latter to such an extent that the roller 3 is pressed against the drum 1 with considerable force. Thusa braking action takes place. Braking could of course also be effected by hand without releasing the tension of the spring, if the roller lever 7" of Fig. 8, is turned by a force applied at 11. J! i The springs must oi course be kept compressed while ready for action and for that purpose a locking-dmice would be required,

if the current-is to be conserved. The. best method for locking is to construct the solenoid compressing spring, in such a way, that it will always retain as much' power, even it the current is very weak, which I will be sutlicient to maintain the spring compressed. Fig. 9 illustrates this method. All magnets having a movable core will require for said core a non-magnetic guiding in order to warrant a frictionless working, but such non-magnetic guiding de creases considerably the carrying power in the end position. If provision is made for a magnetic bridge at this place, the pulling power in the end position can be increase almost twofold, that is to say a certain pulling force, corresponding with that oft-he compressed spring, can be obtained by a far.

In Fig. 9,2?

less consumption of current. designates the core of the solenoid,28 the coil, 29 the casing, and 30 the non-magnetic guiding of brass, bronze, or the like. If the cylindrical core is equipped with a fixed neck or ring 31 in. such a manner that this ring neatly abuts against the easing in the end position of the magnet core,

it will bridge the non-magnetic guiding in the end position and obviouslythe carrying power is almost twice as great. For .the member 31the'eXpression adhering ring could be applied.

Thus it is possible to maintain the ten-. sion of the spring by a weak current, as the closed circuit current, is flowing through the solenoid.

The intensity of the braking power de pends on the strength of the spring and to what extent it is released. If the re-' lease is small,,the less the coreof the solenoid can advance. vided for adjusting the force of the brake previous to a braking action, as the dis- .tance which the plunger of the solenoid is permitted to advance, is limited. This is efiected in a simple manner by adjustably constructing the solenoid, as illustrated more plainly in Fig. 6. In'the latter a slide (16) is cast to the solenoid, a screw spindle (l7) turning in said slide, and adapted to be manipulated from thedrivers place by means of bevel wheels and rope pulley. The driver is thus enabled to do crease or. increase the braking power even during the operation of the train-accord ing to the condition ot-the track and the load. Hewill require less braking power. when the wheels of the car slide on slippery rails and with an empty car, than with an overcrowded car on dry rails. I v P But such regulationwould turn out to be too: circumstantial, if it would take place Thus' a means is pro- -the-idrivers platform." But aiinuchasier --mean's for "controlling th'ei hraking"power "during the=-brak-ingroperation is, available? stops; 'a-iroller mounted-forffrictional conhere in so'far', as the'pulling'force of the solenoid Will act contrary to the forceof "the spring.

If during the braking operation a certain current is led through the solenoid; and which current i must of course be less thanrthat requrre'd forthe-compresact Witha'certain force against the pressure power.

IILFlgJ a switching diagram issh'own lever turnsabout the point 32; On I) '0 c? e are the difierent'positions of said regulating lever,- 33 and 34 areresistances; and

between the switching steps avandce 'a're likewise provided somevresistances; 35 is the "tion and 37'the point" ifroin-wliicl'i current is supplied, for "instance theuover-head con- 'du'ctor. Ifthe driver moves the "handle of the' regulating switch to the position (S) a "sufficiently strong current Willfiow through the solenoidifonth-e' latter to compress the spring. If heinoves tlie handle of the 'i'egulatingswitch to"1th'e= position the resistances 33' and "34 are connected inseries With the coil of the solenoid and the sum of sion* ofvthe spring, the s-aid'rsolenoidwill" these resistances is selected insucha man 'ne'rytha t" the-closed c1r'cu1t=current Will-appeargthat'is to say acertains mall" strength of current, Which -vvill keep-the springs compressed?" If the driver Wants to applythe brakes; he moves' the thusinterrupted for an instaritythe coil35 of the solenoid is free of currentytheplunger of the solenoidadvances and apowerful I braking action would'foll-ow. But assoon --"fl0vvs into the solenoid, Whose pulling'power as explained above will decrease the pressure of the spring. Thus a Weak'braking handle from O'to' w, ivhile'the current is" as hei reaches the? contact a currentagain braker drum; "aaghand associated mith said drum; band stops on said band; stationary stops adapted for association with said band tact with said" brake drum; and means whereby i said Brake band will tightenitse1f 1 around said brake \dnum' when "said roller of the"spi1?ing, +i that is to'say it avill reducethe latter: and in '1consequence1the: braking wv'liicli will'eXpl-ain this operation (R) is a n common regulating switch; Whose regulating contacts with the brake drum.

3. In a' brake-mechanlsnr comprising a vdrum and a brake hand associated .therei with saidband having stops thereon sta-.

tionaryw stops associated" with said: band -stops;'. a:roller adapted to b'e'forced' against a ,said' "drum; and L meansnwherebyl-said band will tighten itseltairoun'dz=tlie drum when theJroll'er is forced against sa-id'gdrum.

4: In a brake mechanism comp-rising a drum and a' -brakenhandassociated there- *svith said band having' stops at each iend coil of the solenoid; 36 is a ground connec-- just suffice to 4; action is'efi'ected to the same extent as the driver by advancing to the' positions b, c andso on IS- connecting up the resistances, the

1 intensity ofthe current in'the" solenoid de-- -oreasesand in consequence itspulling power, so that the pressure of the springs "I claimi 1. In a brake mechanism f comp-rising a' brake "drum; "a band associated with said drum; band stops on said band; stationary stops adapted'fo'r associationwithsaid' -hand stops;-'an'd a roller intermediate said stat-iq ary stops "and connected to said "hand.

2'. In a brake'mechanism' comprising a thereof; stationary "stops: for association with saidband stops; airoller adapted to be forced against said drum; and a connecting member secured to each end oftheb'andand thereof; stationary stops' for association with said loand' stops; roller 'adapted'to contact With said drum ;-and' means whereby an arc of the band ivill engage an arc of the drum when the roller is 'forced against said lorake drum.

6." In a "brakemechanismicomprising a drum and a brake' b'and associated there with; means associated with the ends of said band for preventing rotation of one end of said hand dependent on the direction of rotation of said drumra-roller adapted to he forced against said drum and a connecting membersecu'red -to' each endofthe band and f at theother end to a common point on said roller, midp int lying upon a'smallr diameter than that of the external diameter of thej'roller. I I i 7 In a "brake mechanism comprising a brake drum "a band associated, vviths'aid druinand' having two-ends; aj roller con- "nected to and-intermediate of-the {ends of said band and means ior preventing rotation of-said hand' Whenthe' roller is forced is more andmore increased and accordingly 1 the" braking power,

against said drum.

"8. In a' brake mechanismpomprising a brake drum; a band-"associated With said drum and having two ends 'jmeans associated with the ends of S2L1d" band; for

preventing rotation" of the band; a roller adapted to" contact-With thedrum? and "means connected atyone lend to anmend other end to apoint on the roller.

9. In a brake mechanism comprising a said point 1y; g upon a smaller diameter brake drum; a band associated With said than the diameter of the roller. 10 drum and having two ends; means asso- In testimony whereof I have affixed my ciated With the ends of said band for presignature.

venting rotation of the band; a roller adapt- MAXIMILIAN MULLER,

ed to contact with the drum; and means Witnesses:

connected at one end to an end of said band I E. HOLTZERMAN,

and at the other end to a point on the roller, R, AUSPAEL. 

